cdonate = boolean (1 or 0). Use this to enable and disable the contribute script.
coindonatelimit = integer. Use this to set the amount of coins on hand to autocon
conper = integer from 1 to 100 representing a percentage. Use this to randomize your donations and only con <conper> percent of the time.

I recommend that you put /autocon into your HP bar trigger to spread donations out through combat.